Abstract
The aim of the present study was to quantify the suspended solid concentrations (CSSL) and suspended solid transport (TSSL) in the mixing zone of the Pará River Estuary. This estuary is located at the southeastern extreme of the estuarine complex of the Amazon River, and receives input from Tocantins and Pará rivers and other local tributaries, with a total discharge of approximately 104 m3 s-1. Two field campaigns were conducted to collect samples of Suspended Particulate Matter (SPM) and measure turbidity. Bottom and surface samples were collected hourly throughout a semidiurnal tidal cycle at two points in the estuary (Left Margin [LM]: -0.7287° -48.2408° and Right Margin [RM]: -0.6051° -48.4048°) in both the dry and rainy seasons. The TSSL was determined using a linear correlation between SPM and turbidity. The results indicate that both the RM and LM points were export routes of suspended solids to the adjacent ocean. However, both lateral and seasonal differences were observed in the PRE samples, with the RM point exporting more suspended solids to the adjacent ocean than the LM point. The TSSL was higher in near-bottom layers on the RM, and the lutocline was broader in comparison with the LM. The correlation between the CSSL at the bottom and in the water column was higher on the LM, and indicated that approximately 80% of the CSSL on this margin derives from resuspension. The sum of the evidence indicates that both points export suspended solids to the ocean.
Descriptors:
Suspended particulate matter; Turbidity; Linear regression; Lutocline; Resuspension
